In a chip resistor, which is a kind of comparatively large chip-like electric component, a resistor body or the like is formed of a thick film. Soldering electrodes are also each formed of a thick film. In some comparatively small resistors, electrodes and resistor bodies are formed, using only a thin-film forming technology. Further, in some comparatively small resistors, soldering electrodes are formed by a combination of a thick film and a thin film.
In a chip resistor manufacturing method described in Japanese Patent Application Publication No. 1988-172401 (JP1988-172401A), an alumina substrate for obtaining a large number of or multiple chip resistors is employed. The alumina substrate is capable of being cut and separated in order to obtain individual chip substrates. First, a plurality of thick-film resistor body layers made of RuO2 are formed on the surface of the alumina substrate in a longitudinal direction at constant intervals, by screen printing or the like. Next, at least one pair of C-letter shaped side electrodes are formed so that the side electrodes continuously cover both end portions of the thick-film resistor body layers, both side surfaces of the alumina substrate, and both end portions of the back surface of the alumina substrate. Thin-film forming techniques such as sputtering and ion plating are used in forming the side surface electrodes. Further, a glass coat is formed to cover the entire surface of each resistor body. The glass coat is formed as a protection film when resistance trimming is performed. After the glass coat has been formed, laser trimming is performed. After the trimming has been finished, a protection coat made of glass or the like is formed on the surface of each glass coat. Then, the alumina substrate is cut into individual chip substrates, thereby completing the manufacture of the chip resistors. According to this related art, the thickness of each electrode may be reduced. Consequently, the size of the chip resistor may be reduced.
Japanese Patent Application No. 11-307304 (JP11-307304A) discloses a structure of a chip resistor and a manufacturing method of the chip resistor. In the chip resistor, a pair of surface electrodes are formed on the surface of a ceramic substrate using a thick film. A base electrode layer is then formed on each surface electrode using a thin-film forming technique such as sputtering. A plated Layer is further formed on the base electrode layer.